The present invention relates to an improved butterfly-type valve and actuating means which, although suitable for use in many fluid valving applications, is particularly suited for use as an on-off valve for the engine coolant supply to an automobile heater.
Valves for such an application must be very inexpensive to manufacture and assemble, must operate to provide a reliable seal in the adverse environment found in the engine compartment of an automobile, must reliably seal a liquid which may be loaded with core sand and other impurities, and must be small and lightweight. Although a butterfly-valve has been used for such an application it incorporates a rubber covered pivotal valve element operable within a rigid housing, and has been found to be relatively expensive and difficult to fabricate and assemble. The following is a list of all the patents which applicant has seen in connection with the development of the present valve:
______________________________________ 1,588,445 3,029,063 1,744,798 3,048,191 2,059,687 3,442,488 2,296,213 3,568,975 2,772,850 3,666,235 2,923,523 3,675,681 ______________________________________
It is therefore a primary object of the present invention to provide an improved butterfly-type valve having the aforesaid desirable characteristics and which obviates the disadvantages of known valves.
It is an object of this invention to provide an improved valve utilizing relatively few different parts formed simply of inexpensive materials, using common parts to reduce tooling and inventory costs, having its operating parts floating in or mounted to an elastomeric member to reduce the number and degree of critical tolerances, utilizing a single elastomeric member to provide the dual functions of valve seat and body seal, and incorporating easy to assemble components, whereby fabrication and assembly costs are minimized.
It is an object of this invention to provide an improved valve which is balanced so that it seals equally well against both positive and negative pressures and which utilizes a resilient seat which is washed by the valved fluid to minimize the adverse effects of foreign matter in the fluid, whereby a reliable leakproof valve seal is achieved. A related object resides in the provision of such a valve which by virtue of its balanced nature requires a relatively low opening force.
It is an object of this invention to provide an improved force transmitting linkage for a valve which incorporates force controlling means for preventing over-closing of the valve, whereby a relatively uniform loading of the valve is achieved, a lighter weight, more friction-free actuating shaft may be used, and the need for critical manufacturing tolerances is obviated.
It is an object of this invention to provide an improved technique for affixing an actuating shaft to a butterfly valve element.
It is an object of this invention to provide an improved method of fabricating and assembling a butterfly-type valve.
These and other objects of the invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings.